Liquid crystal display apparatuses have been used in various fields because of their advantageous features such as small thickness, light weight and low power consumption. Among the liquid crystal display apparatuses, the active matrix type liquid crystal display apparatus, in which thin-film transistors (TFTs) are used as pixel switching elements (driving elements), has high performance, such as high contrast ratio and high response speed, and hence has been mainly used in a monitor of a personal computer, a portable TV apparatus, and the like. Therefore, the market scale of the active matrix type liquid crystal display apparatus has been significantly increasing.
Meanwhile, in recent years, in the field of liquid crystal display apparatus, a driving circuit integrated type liquid crystal display apparatus, in which a peripheral driving circuit (driver circuit) for driving a liquid crystal display panel is formed (in which the peripheral driving circuit is monolithically formed) on the same substrate as the substrate having pixel TFTs, and the like, arranged thereon in a matrix form, has been mass-produced. This is because, with the driving circuit integrated type liquid crystal display apparatus, it is possible to obtain features such as, reduction of the picture-frame and the thickness of the panel, cost reduction by elimination of integrated circuit (IC) chips for driving (reduction in the number of components of the liquid crystal display module), and reduction in the number of mounting processes.
Examples of the technique for monolithically forming the peripheral driving circuit include a technique (which may also be referred to as full monolithic technique) for monolithically forming gate drivers (scanning electrode drivers, or gate driving circuits) and source drivers (signal electrode drivers, or signal driving circuits) by using low temperature polysilicon (p-Si) and continuous grain boundary crystal silicon (CGS), and a technique for monolithically forming only gate drivers by using amorphous silicone (a-Si). At present, the former technique tends to be used. On the other hand, as compared with the former technique, the latter technique has such advantages that the process temperature is low, that low-cost glass can be used, that the number of masks is small, and that the number of processes is small. In recent years, the latter technique has also been attracting attention.
Examples of the circuit for configuring the gate driver include a shift register. Shift registers devised in various ways have been proposed (see, for example, Patent Literatures 1 to 3).